The effect of annealing on the generation and detection characteristics of magnetoelastic waves (MEWs) in Fe77.5Si7.5B15 amorphous wires was studied. Annealing after wire-drawing was found to be exceedingly effective in improving the efficiency in high-frequency regions. The wire-drawing is indispensable to eliminate inhomogeneities which may scatter the high-frequency MEWs. The annealing is necessary to soften the magnetic hardness arising from the wire-drawing. It was found that a partial annealing causes a small region, highly sensitive to a driving magnetic field, to develop; this region is made insensitive to the driving field by wire-drawing. The small region serves as an excellent source for generating high-frequency MEWs.